Retinal degenerative diseases are the leading cause of unbeatable blindness in the industrialized world. Individuals with retinitis pigmentosa (RP), one of the most frequently occurring blinding hereditary retinal dystrophies, can have profound spatial contrast sensitivity (CS) deficits of unknown origin. Because contrast processing forms the basis for form, motion, and depth perception, evaluation of CS can provide a sensitive assessment of visual performance deficits. However, CS tests have potentially serious limitations in their current form, and the paucity of information regarding the factors underlying CS deficits is a fundamental impediment to developing better testing strategies. The goals of this award are to: 1) provide the applicant with clinical skills and a fundamental knowledge of ocular diseases;2) apply this knowledge to develop an innovative testing strategy for identifying the mechanisms underlying CS losses in persons with RP. During the mentored phase, the applicant will master clinical vision testing methods, such as electroretinography and retinal imaging, while conducting mentored research. This phase will culminate in the applicant securing a tenure-track faculty position and developing a laboratory focused on determining the relationship between retinal pathophysiology and visual dysfunction. The independent phase will focus on two specific research aims: Aim 1 is to develop an optimized visual-noise-based testing strategy for evaluating letter CS that is not subject to the limitations of current tests. Noise-based techniques provide more information than standard tests because performance is factored into three independent underlying mechanisms: both additive and multiplicative noise within the visual pathway, and the ability to extract the signal from the noise. However, several issues regarding noise-based tests have been identified in pilot work, and these issues must be resolved to establish an optimized test. Aim 2 will apply the optimized testing strategy to persons with RP to identify the factors underlying CS losses. It has been suggested that high levels of additive noise underlie CS deficits in individuals with RP, but empirical data have not been obtained to evaluate this hypothesis